ANALYSIS AND REDESIGNING OF RING BENDING MACHINE

Gajdhar Vrutant*,Thakar Pratik, Prajapati Urvesh, Shaikh Abrar

Laxmi Institute of Technology, Sarigam – Valsad, Gujarat

Corresponding author address:

Mr. Gajdhar Vrutant Student,

Laxmi Institute of Technology, Sarigam – Valsad, Gujarat. Mobile: +91 – 9033******

E-  mail: vrutant53@gmail.com, thakarpratik010@gmail.com, urvesh.prajapati712@gmail.com, abrar10shaikh@gmail.com

ABSTRACT

As the name suggest this project is about to improve the production rate of ring with the use of redesign of ring bending machine. Our project is to analysis and redesign of existing ring bending machine, this machine is use to bend strips in to curvature shape. The problem we defined in industry is that we found the more wastage of raw material, more man power and less efficiency of ring bending machine and time consuming. As per our expected conclusion, after the redesign of this machine, the efficiency of this machine will be increased, number of labours will be reduce, total time for bending of strip will be reduce, better utilization of raw material will be possible with high accuracy.

KEYWORDS: Bending of strips, Redesign of Bending machine, Bending strips, three roller bending pyramid.

INTRODUCTION

INTRODUCTION OF RING BENDING MACHINE

Metal forming can be defined as a process in which the desired size and shapes are obtained through plastic deformation of a material without any significance loss of material. Bending is a metal forming process in which straight length is transformed into a curved length. Roller forming is a continuous bending operation in which a long strip of metal is passed through consecutive sets of rollers, until the desired cross sectional profile is obtained. Roller bending process can be used to deform strips/rings of constant or varying cross sections like circular  or curvature shapes.

The rolling process is usually performed by, a three roll bending machine often called as pyramid type, because of the peculiar arrangement of the three rollers.

The entire process of the roll bending may be divided into three steps:

·         Positioning of blank strip.

·         Lowering of the center roller.

·         Feeding of the strip.

In the very first step, a flat blank raw material of ring is fed into the machine by two rotating side rollers until the ring is properly positioned. In the second step, center roller is displaced downward causes bending of the ring. In the final step, two side rollers rotate again, so that the ring is bent continuously.

The rolling process always began with the crucial operation of pre bending both ends of the ring. This operation eliminated flat spots when rolling a fall cylindrical shape and ensured better closure of the seam. The success of three roller bending process heavily depends on the experience and skill of the operator.

NEW MACHINE:-

LITERATURE REVIEW

M. Hua et al developed, in the paper, an analytical model to study the mechanics of continuous plate edge bending mode of the four roll bending process, solving governing differential equation for the large deflection of an elasto plastic thin plate with an arbitrary

strain hardening law for the material. The effect of material strain hardening on the  mechanics is also studied and compared with those for a perfectly plastic material.[1]

M. Hua et al discussed design consideration, working principle and bending mechanisms the four roller bending machine. Generalized procedure of four roller bending machine is also explained.[2]

Jong Gye Shin et. al in the paper developed a logical procedure to determine the center roller is placement, in the three roll bending process, which is required in the fabrication of curved rectangular plates with a desired curvature. To this end, the mechanics of the process was analyzed by both analytical and finite element approaches. Comparisons of the results reveal that a simple analytical procedure, based on the beam theory, yields a reasonably accurate relationship between the center roller displacement and residual curvature. With further development  and  refinement,  the procedure proposed  in  this  work  has  great  promise for

practical application, particularly forthe automation of the process.[3]

M. B. Bassett Handa et. al discussed about the productivity analysis of manually and power operated sheet bending machine considering time required to complete one pipe, total expenditure required to manufacture one pipe, number of operators and labors.[4]

         Mehar in his M. Tech Thesis studied the manually operated and power operated sheet bending machine. Experimentations were conducted on sheet in order to measure actual no.  of passes, time required to complete bending process etc. Also, productivity of sheet bending process is analyzed in depth. Design of various components of power operated sheet bending machine considering various theories of failure inelastic region and values for bending  force,

power required, spring back radius etc. for different diameters, thicknesses and width of sheet metal has been determined.[7]

Table 1: Summary of literature review of ring bending machine

Sr.No.	Title	Author	Technique	Method
1	Analytical model of machine[1-3]	M. Hua et al	The        effect              of material strain hardening on the mechanics	Governing differential equation for the large deflection of an elasto plastic deformation.
2	Three roller bending pyramid type[4]	M. B. Bassett and           W. Johnson	Bending    of    plate using a three roll	Strain       Analysis       and capacity chart.
3	Determine the center roller displacement[5,6]	Jong        Gye Shin et. al	Analytical and finite element approaches	Simple analytical procedure, based on the beam theory.

4	Modeling                            and computation of the three-roller bending process[7]	Ahmed Ktari	Meshing technique	Two-dimensional finite element model.
5	Analytical model for prediction of force[8]	M.K Chudasama	Deflection of the top roller required for bending	Analytical method to measure no. of passes
6	Time analysis for no. of passes.[9]	P.G. Mehar	Various theories of failure in elastic region and values for bending force	Measuring actual no. of passes.

FUTURE SCOPE

The scopes of the study are encompasses investigation of the difficulties in portable metal strip bending machine. The investigation is starting with stating with the problem statements. The idea of designing a bending machine can be seen clearly through the problem statements, which is a solution of designing a bending machine can be generated to encounter those problems. From this investigation, a literature review can be conducted. In the literature review, it will discuss about the reason to design a bending machine for strip bending, the comparison of existing bending machine, classification of bending machine, working principle of bending machine, etc.

OBJECTIVES

·         To make a bending machine to bend metal ring up to 8 mm.

·         To make on simple working principle.

·         To reduce the time for operation.

·         To make in minimum cost.

·         To increase the production rate.

CONCLUSION

Such type of bending machine more important for small scale work as well as industrial work in less cost and more precision and accuracy of different type of pipe bending. The machine capacity can be increased according to the need. Manual bending tends to minimize wrinkles and can reduce springbuck. By its design the defects can be easily overcome. Simpler design not only reduces the defects but also contributes to fluid pressure test during bending. It

should be noted the tendency to wrinkle and the cross section of tube deformation are reduced. Thus, this approach can be used for bending a thin walled tube over a small radius  of the die, which can be achieved with a conventional method of bending the tube. The objective of the study is to develop a tool that accurately predicts the change of the wall thickness and the cross-section of the strip distortion under different loading conditions.

ACKNOWLEDGMENT

We are thankful to our guide Mr. Jinit Barot for their valuable suggestion and support.

REFERANCES

1. M. Hua, D. H. Sansome, and K. Baines, “Mathematical modeling of theinternal bending moment at the top roller contact in multipass four roll thin plate bending,” J. mater. Process.Technol. vol. 52, pp. 425-459,1995.
2.  M. Hua, D. H. Sansome, K. P. Rao and K. Baines,Continuous four-roll plate bending process: Its bending mechanism and influential parameters, Journal of Materials Processing Technology, 45 (1994) 181-186.
3.    M. Hua, I. M. Cole, K. Baines and K. P. Rao, A formulation for determining the single- pass mechanics of the continuous four-roll thin plate bending process,Journal of Materials Processing Technology, 67 (1997) 189-194.
4.    M. B. Bassett, and W. Johnson, “The bending of plate using a three roll pyramid type plate bending machine,” J. strain Analysis, vol. 1, no. 5,pp. 398, 1996.
5.    Jong Gye Shin, TacJoon Park & Hyunjune Yim Roll Bending”,Tran, ASME, J. Mechanical Design, 123 May 2001, PP 284-290.
6. Jong Gye Shin", Jang Hyun Lee, You II Kim,HyunjuneYim, “Mechanics-Based Determination of theCenter Roller Displacement in Three-Roll Bending forSmoothly Curved Rectangular Plates”, KSMEInternational Journal VoL15. No. 12, 2001, pp. 1655- 1663.
7.  Ahmed Ktari, ZiedAntar, Nader Haddar and KhaledElleuch, “Modeling and Computation of the three-rollerbending process of steel sheets”, Journal of MechanicalScience and Technology, 2012 pp 123-128.
8. M.K Chudasama, M. Hua, “Mechanical analysis of edge bending mode for four-roll plate bending process”,Computational Mechanics, Springer-Verlag 1999, pp 396-40
9.  P. G. Mehar, “Improving the Productivity of Sheet Bending Operation in Pipe Manufacturing Industry”, M.Tech. Thesis, Department of Production Engineering, Y.C.C.E., Nagpur, June 2005.